One approach to separating metals from metal-bearing materials includes subjecting the ground or crushed material to treatment with a chemical solution containing one or more reagents capable of selectively solubilizing the desired metal constituents while leaving the remainder of the metal-bearing material behind. The leach solution may then be treated in further recovery and refining operations to obtain the metal values in a purified form. Despite available technologies, there is a need in the art for improved methods of recovering metal values from metal-bearing materials.